Coolers for compressors



United States Patent M 3,092,980 COOLERS FQR COMPRESSORS John Rutger Munck af Rosenschold, Saltsjobaden, and Jan Graf, Enskede, Sweden, assignors to Atlas Copco Akneboiag, Nacka, Sweden, a corporation of Sweden Filed Mar. 18, 1959, Ser. No. 800,242 Claims priority, application Great Britain Mar. 18, 1958 1 Claim. ((31. 62452) This invention relates to compressed air or gas coolers for compressors such as intermediate coolers and aftercoolers. The invention is particularly directed to the type of coolers which comprise in combination concentric inner and outer casings providing an annular space therebetween for the passage of the compressed air or gas and accommodating a tube coil for a cooling fluid, such as water. One object of the invention is to provide an improved cooler of this type which is simple in manufacture and easy to assemble and in which the inner casing is anchored to the outer casing in an eflicient manner to prevent vibrations. Another object of the invention is to provide a cooler in which the tube coil is readily accessible for cleaning. Other objects will appear as the ensuing description of suitable embodiments of apparatus embodying the invention proceeds.

In the accompanying drawing three embodiments of coolers according to the invention are illustrated by way of example. FIG. 1 is a vertical section through an intermediate cooler and Water separator according to the invention. FIG. 2 is a vertical section of an intermediate cooler according to a second embodiment of the invention, and FIG. 3 is a vertical section and partial side elevation of an aftercooler according to the invention.

The intermediate cooler illustrated in FIG. 1 comprises a cylindrical inner casing 1 and a concentric outer casing 2 forming therebetween an annular space 3 for the passage of compressed air. The inner casing 1 is provided with a dished end cover 4 at the upper end which is welded to the inner casing at 5 to form an air-tight closure of the upper end of the casing 1. At the lower end of the casing 1 a flange 6 is provided which forms an annular seat 7 for the lower end of the outer casing 2 and an external annular sealing surface 8 which together with an internal annular sealing surface 9 at the lower end of the outer casing 2 forms a tapering annular groove in which an O-ring packing 1G fits. The air pressure in the space 3 presses the packing 10 towards the bottom of said groove to provide a perfect seal and to keep the lower end of the casing 1 anchored against side displacement in the casing 2. 11 indicates an inlet opening in the side wall of the casing 2. A coiled and finned tube 12 is disposed in the annular space 3 and provided with a supply pipe 13 and a discharge pipe 14 for cooling liquid. The upper end of the casing 2 is provided with a cover and transverse tube 15 which is welded to the casing 2 and to a second casing 16 arranged substantially parallel with the casing 2. The casings 2 and !16 and tube 15 form together a substantially U-shaped body. A bolt'17 is carried through the cover 15 with an air-tight tit and screwed into the cover 4 to secure the upper end of the casing 1 relative to the casing 2 and to press the flange 6 of the casing 1 against the lower end of the casing 2. The casing 16 forms a water separator and for this purpose an outlet pipe 18 is carried through and secured to a bottom flange 19 of the casing 16 and carries at its inner end a number of helically disposed vanes or fins 2% which cause rotation of the air before the air leaves the intermediate cooler through the pipe 18. The interior of the water separator may be designed as described hereinbelow in connection with the water separator in FIG. 2. Any water that may accumulate as indicated at 21 may be removed by opening a drain cock 22.

Patented June 11, 1963 The intermediate cooler illustrated in FIG. 2 consists of a cylindrical inner casing 23 and a concentric cylindrical outer casing 24. The inner casing 23 is provided at its upper inner side with an anchoring ring 25 in which a number of bolts 26 are screwed. At the lower end the casing .23 forms a number of ports 27 and is welded to an annular flange 28, 29. The casings 23 and 24 form between them an annular space 30 for the passage of compressed air in which space a coiled and finned tube 31 for cooling water is disposed. Cooling water is supplied to said coil through a pipe 32 and is discharged from the coil through a pipe 33 extending through the walls of the outer casing 24. The outer casing 24 has a lower flange 34 and an upper flange 35. The flange 34 has a groove 36 accommodating a packing 37 which forms a seal with an annular sealing surface 38 on the outer portion 28 of the flange 28, 29. The upper flange has a groove 39 for a packing 40 which cooperates with a sealing surface 41 on a cover 42 for the upper end of the outer casing 24. The cover .42 forms an admission chamber 43 for compressed air from the low-pressure cylinder of the compressor which air may be conveyed to the chamber 43 through a pipe 44. The bolts 26 form means for anchoring the upper end of the inner casing to the outer casing 24 and serve to press the flange 28 towards the flange 34 and the flange 35 towards the sealing surface 41 so that an air-tight cooler assembly is obtained in which both ends of the inner casing 23 are properly anchored against axial and sideway displacement. The space within the casing 23 is separated by a partition 45 in an upper chamber 46 which communicates with the space 43 and forms an equalizing chamber, and a lower chamber which is used to accommodate a water separator. The casing 23 has an extra inner wall 47 which together with the casing 23 forms a heat insulating space 48 which may be filled with a suitable heat insulating material, such as fiber glass, or which may simply constitute an air space. 49 is a cylindrical member secured to the flange 29 and 50 is a cylindrical member secured to the partition 45, said members forming between them a space in which a number of helically arranged vanes 51 are arranged to give the compressed air passing said vanes a rotary motion so that any Water or the like contained in the compressed air by centrifugal action is separated in the chamber 52 and collected as indicated at 53 from which space it may be drained by opening a drain cock 54. 55 indicates the discharge tube of the combined aftercooler and water separator which may be connected to the high pressure stage of the compressor.

FIG. 3 illustrates an aftercooler according to the invention which is of general U-shape having two shanks one of which is illustrated in vertical section in FIG. 3. Each shank consists of a cylindrical inner casing 56 and a concentric cylindrical outer casing 57. The outer casings 57 are welded to a bottom plate 58 and to an upper end cover and connecting conduit 59. The inner and outer casings form between them an annular space 69 in which a coiled finned tube 61 for cooling liquid is disposed, said tube being supplied with cooling liquid through a supply pipe 62 and cooling liquid being discharged from the coiled tube 61 through a discharge tube 63. A transverse member or bar 64 is welded across the upper end of the outer casing 57 and has a screw-threaded bore at 65. An arcuate transverse member 66 is provided in the lower end of the casing 57 and a bolt 67 extends through the member 66 and through the inner casing 56 and is screwed into the screw-threaded bore of the member 64. The inner casing is provided adjacent the ends with transverse walls 68 and 69, respectively, which are bored to fit the screw 67 and so that the inner casing is guided on the screw 67. By tightening the screw 67 the inner casing 56 is pressed against the transverse member 64 and the member 66 is pressed against the inner casing 56 and the outer. casing 57 so that both ends of the inner casing are rigidly anchored relative to the outer casing. Compressed air is admitted to the aftercooler at 76 and is pressed through the space 71 and through the annular space 68 and discharged from the cooler at 72.

The coolers above described and illustrated on the drawings should be considered only as examples and the details of the invention may be modified in various different Ways within the scope of the claim,

What we claim is:

A cooler for compressors comprising in combination concentric inner and outer casings providing an annular pressure fluid tight space therebetween, a tube within said annular space for conducting cooling liquid, means in said inner casing forming an air-tight Wall between said annular space and the interior of saidinner casing adjacent one end of said casing preventing fluid flow axially from end to end of said inner casing, means at the opposite end of said inner casing forming an outwardly projecting flange upon which said outer casing may rest with its lower end and forming a wall confining the annular space at said opposite end of the inner casing, a cover for the upper end of the outer casing forming an air passage communicating with 'said annular space, and screw means for connecting said one end of the inner casing with said cover and for pressing said outer casing towards said flange.

References Cited in the file of this patent UNITED STATES PATENTS 1,083,395 Freeman Jan. 6, 1914 1,405,319 Parkin Jan. 31, 1922 1,575,818 Carrier Mar. 9, 1926 1,719,810 'Kucher July 2, 1929 1,863,958 Wulif et al June 21, 1932 2,239,848 Jackson Apr. 29, 1941 2,319,502 Gould May 18, 1943 2,649,698 Goldman Aug. 25, 1953 2,740,268 Jones Apr. 3, 1956 2,783,623 Dodge Mar. 5, 1957 FOREIGN PATENTS 476,911 Great Britain Dec. 17, 1937 

